This invention relates to an engine cylinder head. More particularly, this invention relates to an engine cylinder head for an internal combustion engine. Still more particularly, this invention relates to an internal turbocharger for a cylinder of an internal combustion engine.
A supercharger (or blower) is an externally mounted device that has the capability of increasing the power output of an internal combustion engine and consists mainly of an air compressor (typically belt-driven) that forces intake charge into the cylinders of an enginexe2x80x94which leads to an increase in volumetric efficiency. A supercharger uses power directly from the engine itself to power a compressor. This makes a supercharger a particularly inefficient device, and is one the main reason for its limited popularity. Another cause being that there are many extra external components and modifications required with the use of this device (e.g. intake manifold, pulleys, oil lines, etc.).
A turbocharger (or turbo) is an externally mounted, exhaust-driven supercharger. A typical increase in power provided by a turbo is on the order of 40% (for stock vehicles), yet five fold increases in horsepower (for race cars) have actually been achieved by the addition of this device. The turbocharger (unlike the supercharger) uses the normally wasted heat energy in the exhaust gases of an engine to drive a turbine, which in turn drives a compressor. This makes the turbo a more efficient device than a belt driven supercharger.
Turbos have been used since the early 1900""s, to maximize the efficiency of all types of internal combustion engines. In the late 1980""s, turbocharger usage in the auto industry was at an all-time high. Virtually every automobile company was incorporating turbocharger technology. Consumers were buying turbo cars at an astronomical rate and paying an average $5,000 for this option. This additional cost was easily justified to the consumer by the dramatic increase in the power and efficiency of their automobile engines. The turbo craze was in full effect and turbocharger popularity had suddenly reached epidemic proportions. However, the problems associated with this poorly designed, hundred-year old device would eventually become apparent. Short turbo life, overcrowded engine compartments, and turbo lag were just some of the reasons. Many attempts to resolve these problems proved futile. By the mid 1990""s turbocharger drawbacks were discussed more often than their benefits; by 1999, commercial usage of the turbo was nearly eradicated.
For example, U.S. Pat. No. 5,535,715 uses a geared reciprocating engine to invoke the spherical rotary valve. This concept of geared apparatus applies the geared impellers, and is invoked by means of the exhaust gas.
U.S. Pat. No. 4,010,727 uses a spiral groove in a valve housing to enhance oil lubrication of the valve. This concept is applied to the lubrication of the valve stem by honing the inside surface of the valve guide.
U.S. Pat. No. 4,777,917 uses supercharger cylinders aligned axially with power cylinders and attached by a rod to the piston and feeds air at high pressure and high speed to the cylinder which, in turn, increases the rate of charge consumption.
U.S. Pat. No. 4,735,178 uses a passage between an exhaust manifold and a turbo-supercharger, and then another passageway between the turbo-supercharger and an intake manifold. With a predetermined capacity in the passage, it is possible to dampen the xe2x80x9cpulsing phenomenonxe2x80x9d.
U.S. Pat. No. 3,896,781 has pre-combustion chambers associated with each combustion cylinder and dual rotary valves. One valve controls a lean mixture into the pre-combustion chamber and the other controls a rich mixture into the combustion chamber and the flow of exhaust gases out of the chamber. The valve shafts are geared together and are driven by a crankshaft at a give speed.
Turbochargers are also notorious for bearing failure. Conventional turbos are externally mounted, and usually relatively far from the oil environment of the engine. Their bearings are externally lubricated by long feed lines, which are tapped onto the engine oil pressure fitting. As a result, occurrences of oil starvation are often experienced (especially at engine start-up).
Accordingly, it is an object of the invention to improve the efficiency of an internal combustion engine.
It is another object of the invention to efficiently recover energy from the waste combustion gases of an internal combustion engine.
It is another object of the invention to provide a relatively simple structure for improving the efficiency of an internal combustion engine.
It is another object of the invention to provide a structure which has the benefits of a turbocharger while excluding the major drawbacks of a turbocharger.
Briefly, the invention provides an engine cylinder head for an internal combustion engine that incorporates an internal turbocharger within each pair of intake/exhaust ports.
The engine cylinder head is constructed with at least one cylinder, an intake port for delivering air to the cylinder, and an exhaust port for exhausting combusted gas from the cylinder. In addition, as is conventional, a valve is reciprocally mounted in the intake port for selectively opening and closing the intake port relative to the cylinder and a valve is reciprocally mounted in the exhaust port for selectively opening and closing the exhaust port relative to the cylinder.
In accordance with the invention, a turbine blade assembly is mounted on the valve within the exhaust port for rotation thereof in response to passage of exhausted combustion gas thereover and is operatively coupled to a compressor blade assembly mounted on the valve within the intake port to drive the compressor blade assembly to compress air in the intake port.
The cylinder head functions as a component in an upper section of the internal combustion engine and is essentially a one-piece block of metal (typically, either cast iron or aluminum) that houses all the engine intake/exhaust valves and ports. One of the most important functions of an engine head is to provide a mechanically valved path for engine airflow.
Until now, engine cylinder heads were only passive, meaning that they only provided a pathway for engine airflow. They never actually generated or even promoted airflow. In fact, conventional engine cylinder heads always caused impedance in engine airflow regardless of how well they were designed. The present head, however, is an active device and will always act to increase engine airflow. The head is an ingeniously designed engine head that utilizes exhaust-driven superchargers within its ports.
The compressor and turbine blade assemblies of the cylinder head are located in the intake and exhaust ports respectively, where they belong. Both blades assemblies are coupled via a transmission in the form of a gear cluster that is located in an engine valve cover region. This oil-saturated environment ensures proper lubrication of the gears and rotating drive shafts.
The engine head, in effect, houses a plurality of tiny, internal turbochargers (one per engine cylinder). This allows for tuned supercharging; each cylinder is responsible for its own volumetric efficiency. Also, by using a series of low inertia turbos instead of one large turbo (as in conventional systems), turbo lag becomes virtually non-existent, and a dramatic increase in throttle response is realized as a result. The supercharging mechanism in the engine head is completely self-containedxe2x80x94unlike turbo systems that require many extra external components, some of which are very costly.
Externally, the engine head is virtually identical to a stock engine head. This allows the use of all original externals (intake manifold, exhaust manifold, etc.). The engine head, as a turbocharger, has the ability to increase engine performance and efficiency without using power from the crankshaft, as is the case with a supercharger.